Prepared in cooperation with the U.S. Army Corps of Engineers and the Oregon Department of State Lands Preliminary Assessment of Channel Stability and Bed- Material Transport in the Tillamook Bay Tributaries and Nehalem River Basin, Northwestern Oregon Open-File Report 2012–1187 U.S. Department of the Interior U.S. Geological Survey Cover: Donaldson Bar on the Wilson River. (Photograph by Krista Jones, U.S. Geological Survey, October 13, 2010) Preliminary Assessment of Channel Stability and Bed- Material Transport in the Tillamook Bay Tributaries and Nehalem River Basin, Northwestern Oregon By Krista L. Jones, Mackenzie K. Keith, Jim E. O’Connor, Joseph F. Mangano, and J. Rose Wallick Prepared in cooperation with the U.S. Army Corps of Engineers and the Oregon Department of State Lands Open-File Report 2012–1187 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia 2012 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Suggested citation: Jones, K.L., Keith, M.K, O’Connor, J.E., Mangano, J.F., and Wallick, J.R., 2012, Preliminary assessment of channel stability and bed-material transport in the Tillamook Bay tributaries and Nehalem River basin, northwest- ern Oregon: U.S. Geological Survey Open-File Report 2012–1187, 120 p. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 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Contents Figures .......................................................................................................................................................................... iv Tables ...........................................................................................................................................................................vii Conversion Factors ...................................................................................................................................................... viii Significant Findings ........................................................................................................................................................ 1 Introduction .................................................................................................................................................................... 4 Locations and Reporting Units ....................................................................................................................................... 4 Study Basins .................................................................................................................................................................. 4 Geomorphic and Geologic Setting .............................................................................................................................. 7 Hydrology ................................................................................................................................................................. 11 Historical Channel Descriptions ................................................................................................................................ 16 Settlement and Land Ownership Patterns ................................................................................................................ 17 Natural and Anthropogenic Disturbances Affecting Bed-Material Dynamics ............................................................ 18 Mass Movements .................................................................................................................................................. 19 Logging and Related Transportation Activities ...................................................................................................... 19 Fire ........................................................................................................................................................................ 21 Channel Alterations for Navigation and Flood Control .......................................................................................... 23 Gravel Mining ........................................................................................................................................................ 25 Study Areas and Reaches ........................................................................................................................................ 26 Tillamook River ..................................................................................................................................................... 27 Trask River............................................................................................................................................................ 34 Wilson River .......................................................................................................................................................... 34 Kilchis River .......................................................................................................................................................... 38 Miami River ........................................................................................................................................................... 40 Nehalem River ...................................................................................................................................................... 42 Approach and Key Findings ......................................................................................................................................... 42 Review of Existing Datasets ..................................................................................................................................... 45 Aerial and Orthophotographs ................................................................................................................................ 45 Historical Maps and Survey Data .......................................................................................................................... 50 Previous Hydrologic and Geomorphic Studies ......................................................................................................... 50 Gravel-Operator Information and Surveys ................................................................................................................ 53 Bridge-Inspection Reports ........................................................................................................................................ 60 Specific Gage Analysis ............................................................................................................................................. 68 Delineation of Bars and Channel Features, 1939–2009 ........................................................................................... 72 Distribution and Area of Bars, 2009 ...................................................................................................................... 75 Results for Repeat Bar and Channel Delineation, 1939–2009 .............................................................................. 75 Discussion of Mapped Changes in Bar and Channel Features, 1939–2009 ......................................................... 80 Analyses of Bed-Material Particle Sizes ................................................................................................................. 101 Discussion and Synthesis .......................................................................................................................................... 105 iii Spatial Variation in Bar Conditions ......................................................................................................................... 105 Temporal Trends in Bar and Channel Conditions ................................................................................................... 106 General Bed-Material Transport Conditions ........................................................................................................... 108 Outstanding Issues and Possible Approaches ........................................................................................................... 110 Bed-Material Transport Rates and Sediment Budget ............................................................................................. 110 Detailed Channel Morphology Assessment ............................................................................................................ 112 Legacy and Ongoing Effects of Land Use Activities ............................................................................................... 113 Priority Reaches for Future Analysis....................................................................................................................... 114 Acknowledgments .....................................................................................................................................................